Countable set
= Countable set
{wiki=Countable_set}
A **countable set** is a set that has the same size (cardinality) as some subset of the set of natural numbers. In more formal terms, a set \\( S \\) is countable if there exists a bijection (a one-to-one and onto function) between \\( S \\) and the set of natural numbers \\( \\mathbb\{N\} \\) or a finite subset of \\( \\mathbb\{N\} \\).